US20190366007A1 - Dose limiting mechanism - Google Patents
Dose limiting mechanism Download PDFInfo
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- US20190366007A1 US20190366007A1 US16/332,198 US201716332198A US2019366007A1 US 20190366007 A1 US20190366007 A1 US 20190366007A1 US 201716332198 A US201716332198 A US 201716332198A US 2019366007 A1 US2019366007 A1 US 2019366007A1
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- dose
- injection device
- limit nut
- medicament
- worm gear
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/178—Syringes
- A61M5/20—Automatic syringes, e.g. with automatically actuated piston rod, with automatic needle injection, filling automatically
-
- A—HUMAN NECESSITIES
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- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/178—Syringes
- A61M5/31—Details
- A61M5/315—Pistons; Piston-rods; Guiding, blocking or restricting the movement of the rod or piston; Appliances on the rod for facilitating dosing ; Dosing mechanisms
- A61M5/31533—Dosing mechanisms, i.e. setting a dose
- A61M5/31535—Means improving security or handling thereof, e.g. blocking means, means preventing insufficient dosing, means allowing correction of overset dose
- A61M5/31536—Blocking means to immobilize a selected dose, e.g. to administer equal doses
-
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- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/178—Syringes
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- A61M5/2033—Spring-loaded one-shot injectors with or without automatic needle insertion
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- A61M5/178—Syringes
- A61M5/31—Details
- A61M5/315—Pistons; Piston-rods; Guiding, blocking or restricting the movement of the rod or piston; Appliances on the rod for facilitating dosing ; Dosing mechanisms
- A61M5/31511—Piston or piston-rod constructions, e.g. connection of piston with piston-rod
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- A61M5/315—Pistons; Piston-rods; Guiding, blocking or restricting the movement of the rod or piston; Appliances on the rod for facilitating dosing ; Dosing mechanisms
- A61M5/31533—Dosing mechanisms, i.e. setting a dose
- A61M5/31535—Means improving security or handling thereof, e.g. blocking means, means preventing insufficient dosing, means allowing correction of overset dose
- A61M5/31541—Means preventing setting of a dose beyond the amount remaining in the cartridge
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- A61M5/31545—Setting modes for dosing
- A61M5/31548—Mechanically operated dose setting member
- A61M5/3155—Mechanically operated dose setting member by rotational movement of dose setting member, e.g. during setting or filling of a syringe
- A61M5/31551—Mechanically operated dose setting member by rotational movement of dose setting member, e.g. during setting or filling of a syringe including axial movement of dose setting member
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- A61M5/315—Pistons; Piston-rods; Guiding, blocking or restricting the movement of the rod or piston; Appliances on the rod for facilitating dosing ; Dosing mechanisms
- A61M5/31533—Dosing mechanisms, i.e. setting a dose
- A61M5/31545—Setting modes for dosing
- A61M5/31548—Mechanically operated dose setting member
- A61M5/3155—Mechanically operated dose setting member by rotational movement of dose setting member, e.g. during setting or filling of a syringe
- A61M5/31553—Mechanically operated dose setting member by rotational movement of dose setting member, e.g. during setting or filling of a syringe without axial movement of dose setting member
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- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
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- A61M5/315—Pistons; Piston-rods; Guiding, blocking or restricting the movement of the rod or piston; Appliances on the rod for facilitating dosing ; Dosing mechanisms
- A61M5/31565—Administration mechanisms, i.e. constructional features, modes of administering a dose
- A61M5/31576—Constructional features or modes of drive mechanisms for piston rods
- A61M5/31583—Constructional features or modes of drive mechanisms for piston rods based on rotational translation, i.e. movement of piston rod is caused by relative rotation between the user activated actuator and the piston rod
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- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/178—Syringes
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- A61M5/315—Pistons; Piston-rods; Guiding, blocking or restricting the movement of the rod or piston; Appliances on the rod for facilitating dosing ; Dosing mechanisms
- A61M5/31565—Administration mechanisms, i.e. constructional features, modes of administering a dose
- A61M5/3159—Dose expelling manners
- A61M5/31593—Multi-dose, i.e. individually set dose repeatedly administered from the same medicament reservoir
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- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
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- A61M2005/3125—Details specific display means, e.g. to indicate dose setting
- A61M2005/3126—Specific display means related to dosing
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- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/178—Syringes
- A61M5/31—Details
- A61M5/315—Pistons; Piston-rods; Guiding, blocking or restricting the movement of the rod or piston; Appliances on the rod for facilitating dosing ; Dosing mechanisms
- A61M5/31533—Dosing mechanisms, i.e. setting a dose
- A61M5/31535—Means improving security or handling thereof, e.g. blocking means, means preventing insufficient dosing, means allowing correction of overset dose
- A61M5/31536—Blocking means to immobilize a selected dose, e.g. to administer equal doses
- A61M2005/3154—Blocking means to immobilize a selected dose, e.g. to administer equal doses limiting maximum permissible dose
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- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
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- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
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- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/178—Syringes
- A61M5/31—Details
- A61M5/315—Pistons; Piston-rods; Guiding, blocking or restricting the movement of the rod or piston; Appliances on the rod for facilitating dosing ; Dosing mechanisms
- A61M5/31533—Dosing mechanisms, i.e. setting a dose
- A61M5/31535—Means improving security or handling thereof, e.g. blocking means, means preventing insufficient dosing, means allowing correction of overset dose
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/178—Syringes
- A61M5/31—Details
- A61M5/315—Pistons; Piston-rods; Guiding, blocking or restricting the movement of the rod or piston; Appliances on the rod for facilitating dosing ; Dosing mechanisms
- A61M5/31565—Administration mechanisms, i.e. constructional features, modes of administering a dose
- A61M5/31566—Means improving security or handling thereof
- A61M5/3157—Means providing feedback signals when administration is completed
Definitions
- This disclosure relates to the field of a dose limiting mechanism for an injection device, preferably a reusable pen-injector injection device able to inject a selected dose of medicament.
- Certain injection devices have a dose setting member, or dose selector, via which the user can select a desired dose of medicament to be delivered from a container of medicament associated with the injection device.
- the dose selector can commonly be actuated in one direction to increase the set dose (“dialling up”) and actuated in another direction to decrease the set dose (“dialling down”). As the dose is dialled up or down, this correspondingly increases or decreases stored energy in the device (e.g. in a torsion spring).
- last dose protection or “last dose control”.
- an injection device comprising:
- the dose limit nut conveniently provides both last dose protection and maximum/minimum dose limiting with a single component, reducing the total number of component parts required and simplifying the injection device's design.
- one of said dose limiting endstop features also comprises said last dose rotary endstop feature.
- the dose limiting endstop features may be engageable with one or more formations in said thread of the plunger element.
- the or each formation in said thread may comprise a change in a depth of said thread.
- said drive shaft is arranged concentrically around a first longitudinal axis with said medicament container and at least part of said drive assembly are arranged around a second longitudinal axis which is substantially parallel to but offset from the first longitudinal axis.
- the drive assembly comprises a rotational to axial coupling, where the drive assembly is rotationally drivable by a torsion spring and is arranged to provide said axial force for ejecting the dose from the medicament container.
- said plunger element comprises a rack and the drive assembly further comprises a worm gear engaged in said rack, wherein rotation of said worm gear causes the rack to advance axially forward or backward with respect to said worm gear.
- said last dose rotary endstop feature is engageable with said worm gear.
- the worm gear may be arranged around said first longitudinal axis and said rack may be arranged around said second longitudinal axis.
- the drive assembly may further comprise a worm gear rotational lock engageable with the worm gear, preferably engageable in a forward end thereof, so as to substantially prevent rotation of the worm gear.
- the worm gear rotational lock may be disengageable from the forward end of the worm gear by being pushed axially forward by the drive shaft.
- the drive assembly may further comprise means engageable between the drive shaft and the worm gear and which, when engaged, rotationally lock the drive shaft and worm gear together.
- said dose limit nut has a male thread and said plunger element has a female thread.
- said dose limit nut has a female thread and said plunger element has a male thread.
- said maximum dose is 100 IU and/or said minimum dose is 0 IU.
- the injection device may further comprise a medicament container.
- Medicament may be contained in the medicament container.
- the medicament may be selected from the group comprising: antipsychotic substances including risperidone, hormones, antitoxins, substances for the control of pain, immunosuppressives, substances for the control of thrombosis, substances for the control or elimination of infection, peptides, proteins, human insulin or a human insulin analogue or derivative, polysaccharide, DNA, RNA, enzymes, antibodies, oligonucleotide, antiallergics, antihistamines, anti-inflammatories, corticosteroids, disease modifying anti-rheumatic drugs, erythropoietin, or vaccines, for use in the treatment or prevention of rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, ulcerative colitis, hormone deficiency, toxicity, pain, thrombosis, infection, diabetes mellitus, diabetic retinopathy
- FIG. 1 shows an injection device in accordance with an embodiment of the present invention
- FIG. 2 is a schematic representation of components and a force path of the injection device of FIG. 1 , with the dose limiting features disengaged;
- FIG. 3 is a schematic representation of components and a force path of the injection device of FIG. 1 , with the dose limiting features engaged;
- FIG. 4 is a perspective view of another embodiment of the injection device.
- FIG. 5 is an exploded view of the injection device of FIG. 4 ;
- FIG. 5A is a perspective view showing further detail of the dose limit nut
- FIG. 5B is a perspective view showing further detail of part of the plunger rack
- FIG. 6 is a cross-sectional view of the injection device of FIG. 4 ;
- FIGS. 7 and 7A-7C illustrate incrementing the dose
- FIGS. 8, 8A and 8B illustrate decrementing the dose
- FIGS. 9, and 9A-9D illustrate maximum/minimum dose limiting
- FIGS. 10 and 10 a illustrate over-torque protection
- FIGS. 11 ,11A-11C, 12 and 12A-12B illustrate dose delivery
- FIGS. 13, 13A and 13B illustrate a haptic feedback feature
- FIGS. 14 and 14A-14E illustrate last dose protection
- FIG. 15 is a diagrammatic summary of the key engagement points of the components of the injection device of FIG. 4 , at four stages of dose delivery;
- FIG. 16 summarises schematically the mechanical motion of the drive shaft 140 , dose limit nut 141 , worm gear 142 and plunger rack 145 during dose setting (incrementing the dose);
- FIG. 17 summarises schematically the mechanical motion of the drive shaft 140 , dose limit nut 141 , worm gear 142 and plunger rack 145 during dose delivery;
- FIGS. 18, 18A and 18B show how the units wheel is incremented
- FIGS. 19, 19A and 19B show how the tens wheel is incremented.
- injection device may refer to a device intended for the injection of a medicament to the body and includes devices configured for various delivery methods, such as intradermal, subcutaneous, intramuscular, intravenous, intraosseous, intraperitoneal, intrathecal, epidural, intracardiac, intraarticular, intracavernous, and intravitreal, which may include via a cannula, catheter or similar device.
- Injection device includes syringes of all types, devices that contain said syringes such as auto-injectors, pen-injectors, patch injectors and other similar devices.
- pen-injector may include any device configured to deliver a dose of a medicament from a cartridge.
- the term “user” may refer to a medical practitioner, end user or other user associated therewith.
- Coupled may refer to a connection between components (not necessarily a direct connection; there may be intermediate components therebetween) that enables a force to be transmitted between the components.
- a rotational coupling may refer to a coupling which enables a rotational force to be transmitted between the components.
- operatively connectable may refer to at least two individual components which are releasably connectable together in such a way that the individual components can work together, for example wherein rotation of one of the individual components effects rotation of all of the operatively connected components.
- dose selector may refer to a component or components which, when actuated by a user, enable a dose of medicament to be selected.
- dose indicator may refer to a component or components which provide a display or indication to the user of the selected dose of medicament.
- splines may refer to one or more ridges, ribs or other protrusions on one component which engage in corresponding grooves or the like on a second component to connect the two components together.
- a splined connection may refer to a connection effected by one or more splines.
- forward may refer to a direction towards the end of the injection device from which medicament is expelled.
- backward may refer to a direction away from the end of the injection device from which medicament is expelled.
- driver assembly may refer to an assembly of components capable of using a driving force from, for example, a spring, to eject medicament from an injection device.
- lash may refer to a clearance caused by a gap between mechanical components.
- the term “medicament” may include a substance in liquid or gas form.
- the medicament may be selected from the group comprising of: antipsychotic substances including risperidone, hormones, antitoxins, substances for the control of pain, immunosuppressives, substances for the control of thrombosis, substances for the control or elimination of infection, peptides, proteins, human insulin or a human insulin analogue or derivative, polysaccharide, DNA, RNA, enzymes, antibodies, oligonucleotide, antiallergics, antihistamines, anti-inflammatories, corticosteroids, disease modifying anti-rheumatic drugs, erythropoietin, or vaccines, for use in the treatment or prevention of rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, ulcerative colitis, hormone deficiency, toxicity, pain, thrombosis, infection, diabetes mellitus, diabetic retinopathy, acute coronary syndrome,
- the term “containing the medicament” may refer to the medicament being contained within a suitable medicament container, such as a pre-filled syringe or cartridge, within the injection device.
- a force path may refer to a path between two or more coupled components via which a force can be transmitted between the components.
- a force path may be “interrupted” if there is a gap between the two or more components, i.e. if they are no longer coupled. Transmission of force between coupled components may be “held back” for example by a ratchet arrangement, but in such a case the force path is not “interrupted”.
- a clutch may refer to a component or feature suitable for operatively connecting two component parts either by a positive fit e.g. with teeth, splines, grooves or the like suitable for engaging and disengaging each other, or by a non-positive (e.g. frictional) connection or a combination thereof. Disengaging the clutch may interrupt a force path between two or more coupled components.
- FIG. 1 An injection device 10 according to an embodiment of the present invention is shown in FIG. 1 .
- the injection device 10 is configured to deliver a dose of medicament and extends along a longitudinal axis L between a front end 10 a and a rear end 10 b of the injection device 10 .
- the injection device 10 has a housing 12 and a needle 14 projecting from the housing 12 at the front end 10 a.
- a dose selector 16 is provided at the rear end 10 b and is arranged to permit the selection of a desired dose of medicament for delivery through the needle 12 into an injection site.
- the dose selector 16 is capable of being rotated about the longitudinal axis L with respect to the housing 12 by a user to set the desired dose of medicament to be ejected from the injection device.
- the housing 12 includes an aperture 12 a through which a dose indicator 18 is visible.
- FIG. 2 shows a schematic representation of a force path 26 within the injection device 10 .
- the internal components include the dose selector 16 , a spring 20 , a drive assembly 22 and a medicament container 24 .
- the drive assembly 22 includes a drive shaft 40 , a last dose rotary endstop 42 , a dose limit nut 41 , dose limiting endstops 47 , 48 and a plunger element 45 .
- the spring 20 is configured to provide a drive force to the drive assembly 22 such that the drive assembly 22 may act to dispense medicament from the medicament container 24 .
- the dose selector 16 is coupled to the spring 20 such that a charging force can be transmitted via the force path 26 from the dose selector 16 to the spring 20 in order to charge the spring 20 .
- the spring 20 is charged when a force is applied to the spring 20 so as to elastically deform the spring 20 , and the resulting elastic energy is stored by the spring 20 (i.e. it is prevented from elastically relaxing during a storage phase). Therefore, charging the spring 20 involves increasing the energy stored by the spring 20 .
- the spring 20 is coupled to the drive assembly 22 and is arranged to provide a driving force via the force path 26 thereto when energy stored by the spring 20 is released.
- the spring is capable of storing energy necessary for ejecting the dose of medicament from the injection device.
- the drive assembly 22 acts to expel medicament from the medicament container 24 using the plunger element 45 which is capable of providing an axial force for ejecting a dose of medicament from the container 24 .
- the medicament container 24 may be a pre-filled syringe or cartridge having a barrel and a stopper moveable in the barrel.
- the plunger element 45 may act to move the stopper so as to expel medicament through an opening in the barrel.
- the medicament cartridge may or may not be connected to a needle.
- the spring 20 is a torsion spring
- the spring 20 is charged by applying a torque to wind the spring 20 and elastic energy may be stored by the spring 20 and subsequently released as torque.
- the spring 20 may be charged by applying an axial force to compress the spring 20 and elastic energy may be stored by the spring 20 and subsequently released as an axial force.
- the drive spring 20 when implemented as a torsion spring may be fixed at one end with respect to the housing 12 and rotationally coupled at its other end to the drive shaft 40 of the drive assembly 22 .
- the force path 26 may include one or more torque paths and/or one or more axial force paths, where one or more rotational to axial couplings are employed to switch between rotational and axial forces along the force path 26 .
- one or more intermediate components may be provided between any of the components shown in FIG. 2 .
- the drive shaft 40 and dose limit nut 41 are rotationally coupled together but are able to move axially with respect to one another. As shown in FIG. 2 , as the drive shaft 40 is rotated, force is transmitted along the force path 26 to the dose limit nut 41 which therefore also rotates. The last dose rotary endstop 42 is not engaged (and is therefore not part of the force path 26 ) in FIG. 2 .
- the plunger element 45 is threaded so that the dose limit nut 41 is engaged with said plunger element 45 via said thread, in order to guide relative axial movement between the dose limit nut 41 and the plunger element 45 .
- the dose limit nut 41 is provided with dose limiting endstop features 47 , 48 which are capable of limiting axial travel of the dose limit nut 41 with respect to the plunger element 45 , so as to limit maximum and minimum doses of medicament which can be set by the user.
- the dose limiting endstop features 47 , 48 may engage with changes in the depth of the plunger element thread or formations on the thread, for example.
- the dose limiting endstop features 47 , 48 are not engaged in FIG. 2 (and are therefore not part of the force path 26 ).
- the dose limit nut 41 As the drive shaft 40 is rotated during dose setting, the dose limit nut 41 , which is rotationally coupled with the drive shaft 40 , is also rotated. The dose limit nut 41 travels forwards along the plunger element thread when incrementing the dose and rearwards when decrementing the dose. When one of the dose limiting endstop features 47 , 48 engages, the dose limit nut 41 cannot travel further in that axial direction. Axial travel of the dose limit nut 41 along the plunger element 45 during dose setting is only possible within a range determined by the dose limiting endstop features 47 , 48 . The dose limit nut 41 always remains within this range because, during dose delivery, the dose limit nut 41 does not move axially with respect to the plunger rack 45 .
- Limiting the travel of the dose limit nut 41 in this way sets the maximum and minimum doses of medicament that can be set during dose setting, for example 100 IU and 0 IU respectively.
- FIG. 3 shows the condition in which one of the dose limiting endstops 47 , 48 is engaged and is now part of the force path 26 between the dose limit nut 41 and the plunger element 45 .
- Last dose protection is provided to deal with this situation.
- the last dose protection is provided by the same component as the maximum/minimum dose limiting i.e. the dose limit nut 41 .
- the last dose rotary endstop feature 42 engages, as represented in FIG. 3 .
- the last dose rotary endstop feature 42 prevents further attempted rotation of the dose limit nut 41 by the drive shaft 40 with which it is rotationally coupled.
- An over-torque feature (not illustrated) may be provided to offer an alternate or additional force path if the user continues to attempt to dial up the dose selector 16 .
- the dose limit nut 41 conveniently provides last dose protection and maximum/minimum dose limiting with a single component, reducing the total number of component parts required and simplifying the injection device's design.
- FIGS. 4-19B A further non-limiting embodiment of an injection device according to the present invention is illustrated in FIGS. 4-19B .
- the injection device 100 includes a housing 112 , a dose selector 116 , a dose button 130 and dose button spring 131 , a units wheel 118 , a tens wheel 119 , a dose indicator spring 117 , a drive shaft 140 , a drive spring 120 , a dose limit nut 141 , a worm gear 142 , a worm gear support 143 and a worm gear rotational lock 144 , all located concentrically about a common longitudinal axis L.
- the axis L extends between a front end 100 a and a rear end 100 b of the injection device 100 .
- the injection device 100 has a medicament cartridge 124 supported in a cartridge holder 125 at the front end 100 a of the injection device 100 .
- the cartridge 124 is sealed by an axially-moveable cartridge stopper 126 at its rear end.
- the cartridge and cartridge holder are located concentrically about a second longitudinal axis Lc, such that the cartridge is offset from the main housing 112 , with L and Lc offset from one another as shown in FIG. 6 .
- the dose button 130 is biased rearwardly by the dose button spring 131 .
- the dose selector 116 is provided at the rear end 100 b of the injection device 100 and is arranged to permit the selection of a desired dose of medicament for delivery from the medicament cartridge 124 into an injection site.
- the dose selector 116 is axially constrained with respect to the housing 112 but is rotatable with respect thereto, about axis L.
- the dose selector 116 is rotationally coupled to the drive shaft 140 via pawl features 115 , visible in FIG. 7A , which engage splines 149 on the drive shaft 140 .
- the housing 112 is provided with teeth 113 (visible in FIG. 7B ) on an inside surface thereof for engaging ratchet arms 146 on the drive shaft 140 .
- Tabs 114 on the dose selector 116 are capable of depressing the drive shaft ratchet arms 146 when required, as shown in FIG. 8B .
- the housing 112 is also provided with ramp features 111 (visible in FIG. 12A ) which facilitate disengagement of the ratchet arms 146 from the inside surface of the housing 112 when required.
- a dose indicator is disposed within the housing 112 and displays reference indicia, such as numbers or symbols, to indicate the level of dose selected by the dose selector 116 .
- the housing 112 includes an aperture 112 a through which the dose indicator is visible.
- the dose indicator comprises the units wheel 118 for displaying units and the tens wheel 119 for displaying tens.
- the units wheel 118 is selectively engageable with the tens wheel to increment the tens wheel each time the units wheel moves through units 0 to 9.
- the units wheel 118 is rotationally coupled to the drive shaft 140 .
- biasing means in the form of dose indicator spring 117 biases the units wheel 118 and tens wheel 119 axially rearwardly in the housing.
- the housing 112 has features on an inside surface thereof for engaging with the units wheel 118 and the tens wheel 119 .
- the tens housing feature comprises one or more axially forwardly extending formations 108 which may be equally spaced around the internal circumference of the housing 112 .
- the formations 108 engage with corresponding axially rearwardly extending formations 119 b at the rear of the tens wheel 119 .
- the tens housing feature formations 108 and the tens wheel formations 119 b may be teeth, notches, castellations or any other shaped formations that, when engaged together, prevent relative rotation between the tens wheel 119 and the housing 112 .
- the units housing feature is an axially forwardly extending formation 107 having a cam surface which can engage with an axially rearwardly extending formation 118 b on the units wheel 118 in order to push the units wheel 118 axially forwards.
- Teeth 118 a on the front end of the units wheel 118 are engageable with correspondingly shaped teeth 119 a at the rear end of the tens wheel 119 .
- the teeth 119 a (for engaging the units wheel) and the tens wheel formations 119 b (for engaging the housing) may be concentrically arranged around the longitudinal axis of the injection device, with the teeth 119 a radially inward of the formations 119 b.
- the drive spring 120 is a torsion spring which is fixed at one end with respect to the housing 112 and rotationally coupled at its other end to the drive shaft 140 via the units wheel 118 .
- a worm gear arrangement which comprises a worm gear 142 meshed with a toothed plunger rack 145 located within the housing 112 .
- the worm gear 142 drives the plunger rack 145 forward which, in turn, pushes against the cartridge stopper 126 to deliver a dose of medicament.
- a splined clutch 150 at the forward end of the drive shaft 140 enables the worm gear 142 and drive shaft 140 to be splined together during dose delivery but not during dose setting, described in more detail later.
- the worm gear rotational lock 144 is engaged in the forward end of the worm gear 142 , preventing rotation thereof.
- the worm gear rotational lock 144 is capable of being pushed axially forward by the drive shaft 140 in order to disengage the lock from the worm gear 142 .
- the dose limit nut 141 is keyed to the drive shaft 140 so that they are rotationally coupled but not axially coupled.
- the dose limit nut 141 is engaged with the teeth of the plunger rack 145 and can travel axially forward and backward along the plunger rack 145 as the dose is incremented or decremented respectively.
- the axial range within which the dose limit nut 141 can travel along the plunger rack 145 is determined by dose limit nut endstop features 141 a, 141 b which can engage features 147 , 148 on the plunger rack thread to serve as endstops for the travel of the dose limit nut 141 .
- FIG. 5A shows the maximum dose limit nut endstop feature 141 a and the minimum dose limit nut endstop feature 141 b in more detail.
- Endstops 141 a, 141 b are able to engage features 147 , 148 respectively on the plunger rack 145 ( FIG. 5B ). These features 147 , 148 are preferably changes in the depth of or formations on the plunger rack thread, past which the dose limit nut 141 cannot travel.
- the dose limit nut 141 rotates about axis L with the drive shaft 140 to which it is keyed, but it does not move axially with respect to the plunger rack 145 with which it is engaged, thus always keeping the dose limit nut 141 within the range defined by the max/min dose endstops 141 a, 141 b.
- the user grips the dose selector 116 and rotates it clockwise about axis L, with respect to the housing 112 , in order to increment the dose and charge the drive spring 120 .
- the dose selector 116 is turned clockwise, the pawl features 115 engaging the splines 149 on the drive shaft 140 cause the drive shaft 140 to also be driven clockwise, as shown in FIG. 7A .
- the ratchet arms 146 on the drive shaft 140 engage with the teeth 113 on the inside surface of the housing 112 to prevent un-winding by the drive spring 120 , as shown in FIG. 7B .
- the drive shaft 140 is splined to the units wheel 118 which charges or torques up the drive spring 120 .
- torque is transferred from the dose selector 116 to the drive spring 120 directly through the dose indicator, i.e. the units wheel 118 .
- the dose selector 116 When it is desired to decrement the selected dose, the dose selector 116 is turned anti-clockwise. As shown in FIG. 8A , as the dose selector 116 is turned anti-clockwise, there is a small amount of backlash at point A such that the dose selector 116 can rotate slightly with respect to the drive shaft 140 . This small relative movement is sufficient to allow the tabs 114 on the dose selector 116 to depress the drive shaft ratchet arms 146 so that they can click past the housing teeth 113 , allowing the drive spring to unwind slightly before the ratchet arms 146 catch again on the next housing tooth 113 . This is represented in FIG. 8B . Each decrement preferably equates to 1 IU (“international unit”) of medicament.
- the dose limit nut 141 As the drive shaft 140 is rotated during dose setting, the dose limit nut 141 , which is keyed to the drive shaft 140 , is also rotated ( FIG. 9A ). The dose limit nut 141 travels forwards when incrementing the dose and rearwards when decrementing the dose ( FIG. 9B ). The dose limit nut 141 is engaged in the thread of the plunger rack 145 . Endstop features 147 , 148 are located on the plunger rack 145 , past which the dose limit nut 141 cannot travel ( FIG. 9C ). These endstop features 147 , 148 may be changes in the depth of the thread. As shown in FIG.
- the dose selector pawl features 115 will flex radially outwardly to allow them to skip past splines 149 on the drive shaft 140 .
- the interfacing surface areas of the pawl features 115 and/or splines 149 act as a cam lever, preferably having a matching angle and/or a defined static and dynamic surface friction at the interface surface.
- the over-torque for flexing out the dose pawl features 115 to skip past spline 149 is preferably at least 10% higher than the torque required for dialling up (incrementing) or dialling down (decrementing) the dose indicator 18 , 118 .
- the dialling up torque can be 30 to 80 Nmm, preferably less than 60 Nmm, more preferably 30 to 50 Nmm.
- the dialling down torque can be 20 to 60 Nmm, preferably less than 50 Nmm, more preferably 30 to 40 Nmm.
- the over-torque in the dialling up direction may be different to the over-torque in dialling down direction.
- the outward flexing force and/or strength of one flexible pawl arm 115 could be lower compared to a second flexible pawl arm.
- FIG. 16 summarises schematically the mechanical motion of the drive shaft 140 , dose limit nut 141 , worm gear 142 and plunger rack 145 during dose setting (incrementing the dose).
- the drive shaft 140 rotates clockwise.
- the dose limit nut 141 rotates clockwise and advances forwards with respect to the plunger rack 145 .
- the user presses the dose button 130 against the bias of the dose button spring 131 as shown in FIG. 11A .
- the drive shaft 140 is splined to the units wheel 118 , it is free to slide axially with respect thereto ( FIG. 11B ).
- the splined clutch 150 between the drive shaft and the worm gear 142 engages ( FIG. 11C , FIG. 15 —Worm Gear Clutch 150 ).
- the drive element, in particular the worm gear 142 and the drive shaft 140 engage after 0.5 mm to 1.5 mm advancement of the dose button 130 , more preferably after 0.8 mm to 1.2 mm advancement of the dose button 130 .
- the ratchet arms 146 on the drive shaft 140 begin to disengage from the inside surface of the housing 112 aided by ramp features 111 ( FIG. 12A , FIG. 15 —Hold Ratchet).
- the hold ratchet in particular the ratchet arms 146 on the drive shaft 140 start to disengage from the structured, in particular toothed surface of the housing 112 after 1.5 mm to 2.5 mm advancement of the dose button 130 , more preferably after 1.6 mm to 1.9 mm advancement of the dose button 130 .
- the splines 149 coupling the drive shaft 140 to the dose selector 116 disengage ( FIG. 12B , FIG. 15 —Over torque ratchet).
- the over torque ratchet in particular the drive shaft splines 149 on the drive shaft 140 start to disengage from the dose selector pawls 115 after 1.5 mm to 3.5 mm of advancement of the dose button 130 , more preferably after 2 mm to 3 mm advancement of the dose button 130 .
- the dose indicator and drive shaft 140 are now free to rotate about longitudinal axis L.
- the drive spring 120 drives the units wheel 118 to rotate about longitudinal axis L.
- the units wheel 118 drives the drive shaft 140 which drives the worm gear 142 .
- FIG. 17 summarises schematically the mechanical motion of the drive shaft 140 , dose limit nut 141 , worm gear 142 and plunger rack 145 during dose delivery.
- the drive shaft 140 , dose limit nut 141 and worm gear 142 all rotate anti-clockwise. Only the plunger rack 145 advances forwards.
- the dose limit nut 141 rotates with the drive shaft 140 but does not move axially with the plunger rack 145 .
- the dose limit nut 141 and the drive worm gear 142 preferably have the same thread pitch.
- the worm gear 142 actuates the plunger rack 145 to move axially forwards causing the cartridge stopper 126 to be driven into the cartridge in order to expel medicament thus delivering the selected dose.
- the dose button spring 131 returns the dose button 130 and drive shaft 140 to their original starting positions. This axially rearward movement disengages the worm gear clutch 150 and re-engages the drive shaft ratchet arms 146 with the housing 112 thereby stopping dose delivery.
- the drive shaft ratchet arms 146 run (rotationally) on a relatively smooth track 110 on the inside surface of the housing 112 ( FIG. 13A ).
- this track could be modified to include ridges 109 which would provide audible/haptic feedback to the user during dose delivery ( FIG. 13B ).
- the ridges 109 are conveniently placed relatively close to the user's fingers.
- Last dose protection is provided to deal with this situation.
- the last dose protection is provided by the same feature as the max/min dose limiting i.e. the dose limit nut 141 .
- the plunger rack 145 and dose limit nut 141 have advanced axially forwards such that the dose limit nut 141 is approaching the worm gear 142 .
- the worm gear 142 serves as an endstop, stopping the dose limit nut 141 from moving further forwards and before the maximum dose limit feature 147 on the plunger rack 145 is reached ( FIG. 14A ).
- it is the dose limit nut endstop feature for maximum dose limiting 141 a which engages the worm gear 142 .
- FIG. 15 is a diagrammatic summary of the key engagement points of the injection device components, at four stages of dose delivery.
- the user rotates the dose selector 116 which also drives the drive shaft 140 around.
- Ratchet arms 146 interact with teeth 113 in the housing 112 to prevent unwinding ( FIG. 18A ).
- the drive shaft 140 is splined to the units wheel 118 which, as it turns, increments the displayed unit ( FIG. 18B ).
- the units wheel 118 and tens wheel 119 are biased rearwardly by dose indicator spring 117 . Twice per revolution of the units wheel 118 , the units wheel 118 is moved axially forwards by the cam surface of the units housing feature 107 engaging with the formation 118 b on the units wheel 118 . This axially forward movement causes the teeth 118 a of the units wheel 118 to engage with the teeth 119 a of the tens wheel 119 ( FIG. 19A ).
- the selectable and settable dose range is 1 to 100 IU, with a minimum dose setting of 1 IU, wherein per 360 degree rotation of the dose selector 116 , 20 to 30 IU may be set.
- the units wheel 118 and tens wheel 119 arrangement permits indication of the set IU dose by two digits, a much larger font size for the indicated dose number is usable, thus the arrangement affords better readability of the set dose and usability of the injection device 10 , 100 .
- a dose limit nut 141 and a plunger element are each threaded so that the dose limit nut 141 is engaged with said plunger element 145 via said thread, in order to guide relative axial movement between the dose limit nut 141 and the plunger element 145 .
- the thread is provided with dose limiting endstops 147 , 148 which are capable of limiting axial travel of said dose limit nut 141 with respect to said plunger element 145 , so as to limit maximum and minimum doses of medicament which can be set by the user.
- the dose limit nut 141 is also engageable with a last dose rotary endstop (worm gear 142 ) which prevents further rotation of the dose limit nut 141 with respect to the drive shaft 140 so as to prevent the user setting a dose that is greater than an injectable volume of medicament remaining in said medicament container.
- a last dose rotary endstop worm gear 142
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Abstract
Description
- This disclosure relates to the field of a dose limiting mechanism for an injection device, preferably a reusable pen-injector injection device able to inject a selected dose of medicament.
- Certain injection devices have a dose setting member, or dose selector, via which the user can select a desired dose of medicament to be delivered from a container of medicament associated with the injection device. The dose selector can commonly be actuated in one direction to increase the set dose (“dialling up”) and actuated in another direction to decrease the set dose (“dialling down”). As the dose is dialled up or down, this correspondingly increases or decreases stored energy in the device (e.g. in a torsion spring).
- During dose setting, it is desirable to be able to prevent a user from being able to dial up a dose that is larger than the quantity of medicament remaining in the container. This feature may be referred to as “last dose protection” or “last dose control”.
- Examples of injection devices with last dose protection features are described in WO2011/068531 (Becton Dickinson), WO01/19434 (Novo Nordisk) and WO2006/086983 (Novo Nordisk).
- In accordance with an aspect of the present invention there is provided an injection device comprising:
-
- a. a dose selector, rotatable by a user to set a dose to be ejected from the injection device,
- b. a drive assembly including a drive shaft and a plunger element configured to move a stopper so as to expel medicament through an opening in a medicament container, the drive assembly being capable of providing an axial force for ejecting a dose of medicament from the medicament container,
- c. a dose limit nut rotationally coupled to but not axially coupled to said drive shaft,
wherein said plunger element is threaded so that the dose limit nut is engaged with said plunger element via said thread, in order to guide relative axial movement between the dose limit nut and the plunger element,
wherein said dose limit nut is provided with dose limiting endstop features which are capable of limiting axial travel of said dose limit nut with respect to said plunger element, so as to limit maximum and minimum doses of medicament which can be set by the user, and
wherein said dose limit nut further comprises a last dose rotary endstop feature which prevents further rotation of said dose limit nut with respect to said drive shaft so as to prevent the user setting a dose that is greater than an injectable volume of medicament remaining in said medicament container.
- The dose limit nut conveniently provides both last dose protection and maximum/minimum dose limiting with a single component, reducing the total number of component parts required and simplifying the injection device's design.
- In certain embodiments, one of said dose limiting endstop features also comprises said last dose rotary endstop feature. The dose limiting endstop features may be engageable with one or more formations in said thread of the plunger element. The or each formation in said thread may comprise a change in a depth of said thread.
- In certain embodiments, said drive shaft is arranged concentrically around a first longitudinal axis with said medicament container and at least part of said drive assembly are arranged around a second longitudinal axis which is substantially parallel to but offset from the first longitudinal axis.
- Preferably, the drive assembly comprises a rotational to axial coupling, where the drive assembly is rotationally drivable by a torsion spring and is arranged to provide said axial force for ejecting the dose from the medicament container.
- In certain embodiments, said plunger element comprises a rack and the drive assembly further comprises a worm gear engaged in said rack, wherein rotation of said worm gear causes the rack to advance axially forward or backward with respect to said worm gear. Preferably, said last dose rotary endstop feature is engageable with said worm gear. The worm gear may be arranged around said first longitudinal axis and said rack may be arranged around said second longitudinal axis. The drive assembly may further comprise a worm gear rotational lock engageable with the worm gear, preferably engageable in a forward end thereof, so as to substantially prevent rotation of the worm gear. The worm gear rotational lock may be disengageable from the forward end of the worm gear by being pushed axially forward by the drive shaft. The drive assembly may further comprise means engageable between the drive shaft and the worm gear and which, when engaged, rotationally lock the drive shaft and worm gear together.
- In certain embodiments, said dose limit nut has a male thread and said plunger element has a female thread. Alternatively, said dose limit nut has a female thread and said plunger element has a male thread.
- Preferably said maximum dose is 100 IU and/or said minimum dose is 0 IU.
- The injection device may further comprise a medicament container. Medicament may be contained in the medicament container. In certain embodiments, the medicament may be selected from the group comprising: antipsychotic substances including risperidone, hormones, antitoxins, substances for the control of pain, immunosuppressives, substances for the control of thrombosis, substances for the control or elimination of infection, peptides, proteins, human insulin or a human insulin analogue or derivative, polysaccharide, DNA, RNA, enzymes, antibodies, oligonucleotide, antiallergics, antihistamines, anti-inflammatories, corticosteroids, disease modifying anti-rheumatic drugs, erythropoietin, or vaccines, for use in the treatment or prevention of rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, ulcerative colitis, hormone deficiency, toxicity, pain, thrombosis, infection, diabetes mellitus, diabetic retinopathy, acute coronary syndrome, angina, myocardial infarction, atherosclerosis, cancer, macular degeneration, allergy, hay fever, inflammation, anaemia, or myelodysplasia, or in the expression of protective immunity.
- Embodiments of the invention are further described hereinafter, by way of example only, with reference to the accompanying drawings, in which:
-
FIG. 1 shows an injection device in accordance with an embodiment of the present invention; -
FIG. 2 is a schematic representation of components and a force path of the injection device ofFIG. 1 , with the dose limiting features disengaged; -
FIG. 3 is a schematic representation of components and a force path of the injection device ofFIG. 1 , with the dose limiting features engaged; -
FIG. 4 is a perspective view of another embodiment of the injection device; -
FIG. 5 is an exploded view of the injection device ofFIG. 4 ; -
FIG. 5A is a perspective view showing further detail of the dose limit nut; -
FIG. 5B is a perspective view showing further detail of part of the plunger rack; -
FIG. 6 is a cross-sectional view of the injection device ofFIG. 4 ; -
FIGS. 7 and 7A-7C illustrate incrementing the dose; -
FIGS. 8, 8A and 8B illustrate decrementing the dose; -
FIGS. 9, and 9A-9D illustrate maximum/minimum dose limiting; -
FIGS. 10 and 10 a illustrate over-torque protection; -
FIGS. 11 ,11A-11C, 12 and 12A-12B illustrate dose delivery; -
FIGS. 13, 13A and 13B illustrate a haptic feedback feature; -
FIGS. 14 and 14A-14E illustrate last dose protection; -
FIG. 15 is a diagrammatic summary of the key engagement points of the components of the injection device ofFIG. 4 , at four stages of dose delivery; -
FIG. 16 summarises schematically the mechanical motion of thedrive shaft 140,dose limit nut 141,worm gear 142 andplunger rack 145 during dose setting (incrementing the dose); -
FIG. 17 summarises schematically the mechanical motion of thedrive shaft 140,dose limit nut 141,worm gear 142 andplunger rack 145 during dose delivery; -
FIGS. 18, 18A and 18B show how the units wheel is incremented; and -
FIGS. 19, 19A and 19B show how the tens wheel is incremented. - In the present disclosure, the following terms may be understood in view of the below explanations:
- The term “injection device” may refer to a device intended for the injection of a medicament to the body and includes devices configured for various delivery methods, such as intradermal, subcutaneous, intramuscular, intravenous, intraosseous, intraperitoneal, intrathecal, epidural, intracardiac, intraarticular, intracavernous, and intravitreal, which may include via a cannula, catheter or similar device. Injection device includes syringes of all types, devices that contain said syringes such as auto-injectors, pen-injectors, patch injectors and other similar devices.
- The term “pen-injector” may include any device configured to deliver a dose of a medicament from a cartridge.
- The term “user” may refer to a medical practitioner, end user or other user associated therewith.
- The term “coupling” may refer to a connection between components (not necessarily a direct connection; there may be intermediate components therebetween) that enables a force to be transmitted between the components.
- The term “a rotational coupling” may refer to a coupling which enables a rotational force to be transmitted between the components.
- The term “operatively connectable” may refer to at least two individual components which are releasably connectable together in such a way that the individual components can work together, for example wherein rotation of one of the individual components effects rotation of all of the operatively connected components.
- The term “dose selector” may refer to a component or components which, when actuated by a user, enable a dose of medicament to be selected.
- The term “dose indicator” may refer to a component or components which provide a display or indication to the user of the selected dose of medicament.
- The term “splines” may refer to one or more ridges, ribs or other protrusions on one component which engage in corresponding grooves or the like on a second component to connect the two components together.
- The term “a splined connection” may refer to a connection effected by one or more splines.
- The term “forward” or “forwards” may refer to a direction towards the end of the injection device from which medicament is expelled.
- The term “backward”, “backwards”, “rearwards” or “rearwardly” may refer to a direction away from the end of the injection device from which medicament is expelled.
- The term “drive assembly” may refer to an assembly of components capable of using a driving force from, for example, a spring, to eject medicament from an injection device.
- The term “backlash” may refer to a clearance caused by a gap between mechanical components.
- The term “medicament” may include a substance in liquid or gas form. The medicament may be selected from the group comprising of: antipsychotic substances including risperidone, hormones, antitoxins, substances for the control of pain, immunosuppressives, substances for the control of thrombosis, substances for the control or elimination of infection, peptides, proteins, human insulin or a human insulin analogue or derivative, polysaccharide, DNA, RNA, enzymes, antibodies, oligonucleotide, antiallergics, antihistamines, anti-inflammatories, corticosteroids, disease modifying anti-rheumatic drugs, erythropoietin, or vaccines, for use in the treatment or prevention of rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, ulcerative colitis, hormone deficiency, toxicity, pain, thrombosis, infection, diabetes mellitus, diabetic retinopathy, acute coronary syndrome, angina, myocardial infarction, atherosclerosis, cancer, macular degeneration, allergy, hay fever, inflammation, anaemia, or myelodysplasia, or in the expression of protective immunity.
- When referring to the injection device, the term “containing the medicament” may refer to the medicament being contained within a suitable medicament container, such as a pre-filled syringe or cartridge, within the injection device.
- The term “a force path” may refer to a path between two or more coupled components via which a force can be transmitted between the components. A force path may be “interrupted” if there is a gap between the two or more components, i.e. if they are no longer coupled. Transmission of force between coupled components may be “held back” for example by a ratchet arrangement, but in such a case the force path is not “interrupted”.
- The term “a clutch” may refer to a component or feature suitable for operatively connecting two component parts either by a positive fit e.g. with teeth, splines, grooves or the like suitable for engaging and disengaging each other, or by a non-positive (e.g. frictional) connection or a combination thereof. Disengaging the clutch may interrupt a force path between two or more coupled components.
- An
injection device 10 according to an embodiment of the present invention is shown inFIG. 1 . Theinjection device 10 is configured to deliver a dose of medicament and extends along a longitudinal axis L between afront end 10 a and arear end 10 b of theinjection device 10. Theinjection device 10 has ahousing 12 and aneedle 14 projecting from thehousing 12 at thefront end 10 a. Adose selector 16 is provided at therear end 10 b and is arranged to permit the selection of a desired dose of medicament for delivery through theneedle 12 into an injection site. Thedose selector 16 is capable of being rotated about the longitudinal axis L with respect to thehousing 12 by a user to set the desired dose of medicament to be ejected from the injection device. Thehousing 12 includes anaperture 12 a through which adose indicator 18 is visible. -
FIG. 2 shows a schematic representation of aforce path 26 within theinjection device 10. The internal components include thedose selector 16, aspring 20, adrive assembly 22 and amedicament container 24. Thedrive assembly 22 includes adrive shaft 40, a lastdose rotary endstop 42, adose limit nut 41, dose limiting endstops 47, 48 and aplunger element 45. Thespring 20 is configured to provide a drive force to thedrive assembly 22 such that thedrive assembly 22 may act to dispense medicament from themedicament container 24. - The
dose selector 16 is coupled to thespring 20 such that a charging force can be transmitted via theforce path 26 from thedose selector 16 to thespring 20 in order to charge thespring 20. Thespring 20 is charged when a force is applied to thespring 20 so as to elastically deform thespring 20, and the resulting elastic energy is stored by the spring 20 (i.e. it is prevented from elastically relaxing during a storage phase). Therefore, charging thespring 20 involves increasing the energy stored by thespring 20. - The
spring 20 is coupled to thedrive assembly 22 and is arranged to provide a driving force via theforce path 26 thereto when energy stored by thespring 20 is released. - The spring is capable of storing energy necessary for ejecting the dose of medicament from the injection device.
- The
drive assembly 22 acts to expel medicament from themedicament container 24 using theplunger element 45 which is capable of providing an axial force for ejecting a dose of medicament from thecontainer 24. In certain embodiments, themedicament container 24 may be a pre-filled syringe or cartridge having a barrel and a stopper moveable in the barrel. In such embodiments, theplunger element 45 may act to move the stopper so as to expel medicament through an opening in the barrel. In certain embodiments of the invention, the medicament cartridge may or may not be connected to a needle. - In embodiments where the
spring 20 is a torsion spring, thespring 20 is charged by applying a torque to wind thespring 20 and elastic energy may be stored by thespring 20 and subsequently released as torque. - In embodiments where the
spring 20 is a compression spring, thespring 20 may be charged by applying an axial force to compress thespring 20 and elastic energy may be stored by thespring 20 and subsequently released as an axial force. - The
drive spring 20 when implemented as a torsion spring may be fixed at one end with respect to thehousing 12 and rotationally coupled at its other end to thedrive shaft 40 of thedrive assembly 22. - In certain embodiments, the
force path 26 may include one or more torque paths and/or one or more axial force paths, where one or more rotational to axial couplings are employed to switch between rotational and axial forces along theforce path 26. Indeed, in certain embodiments, one or more intermediate components may be provided between any of the components shown inFIG. 2 . - The
drive shaft 40 anddose limit nut 41 are rotationally coupled together but are able to move axially with respect to one another. As shown inFIG. 2 , as thedrive shaft 40 is rotated, force is transmitted along theforce path 26 to thedose limit nut 41 which therefore also rotates. The lastdose rotary endstop 42 is not engaged (and is therefore not part of the force path 26) inFIG. 2 . - The
plunger element 45 is threaded so that thedose limit nut 41 is engaged with saidplunger element 45 via said thread, in order to guide relative axial movement between thedose limit nut 41 and theplunger element 45. Thedose limit nut 41 is provided with dose limiting endstop features 47, 48 which are capable of limiting axial travel of thedose limit nut 41 with respect to theplunger element 45, so as to limit maximum and minimum doses of medicament which can be set by the user. The dose limiting endstop features 47, 48 may engage with changes in the depth of the plunger element thread or formations on the thread, for example. The dose limiting endstop features 47, 48 are not engaged inFIG. 2 (and are therefore not part of the force path 26). - As the
drive shaft 40 is rotated during dose setting, thedose limit nut 41, which is rotationally coupled with thedrive shaft 40, is also rotated. Thedose limit nut 41 travels forwards along the plunger element thread when incrementing the dose and rearwards when decrementing the dose. When one of the dose limiting endstop features 47, 48 engages, thedose limit nut 41 cannot travel further in that axial direction. Axial travel of thedose limit nut 41 along theplunger element 45 during dose setting is only possible within a range determined by the dose limiting endstop features 47, 48. Thedose limit nut 41 always remains within this range because, during dose delivery, thedose limit nut 41 does not move axially with respect to theplunger rack 45. - Limiting the travel of the
dose limit nut 41 in this way sets the maximum and minimum doses of medicament that can be set during dose setting, for example 100 IU and 0 IU respectively. -
FIG. 3 shows the condition in which one of the dose limiting endstops 47, 48 is engaged and is now part of theforce path 26 between thedose limit nut 41 and theplunger element 45. - When the
medicament cartridge 24 is relatively empty, after several doses have already been delivered therefrom, it is undesirable for the user to be able to select a dose that is larger than the available quantity of medicament remaining. Last dose protection is provided to deal with this situation. Conveniently, the last dose protection is provided by the same component as the maximum/minimum dose limiting i.e. thedose limit nut 41. - During dose setting, if the user attempts to set a dose that is greater than the available injectable volume of medicament remaining in the
container 24, the last dose rotary endstop feature 42 engages, as represented inFIG. 3 . The last dose rotary endstop feature 42 prevents further attempted rotation of thedose limit nut 41 by thedrive shaft 40 with which it is rotationally coupled. An over-torque feature (not illustrated) may be provided to offer an alternate or additional force path if the user continues to attempt to dial up thedose selector 16. - The
dose limit nut 41 conveniently provides last dose protection and maximum/minimum dose limiting with a single component, reducing the total number of component parts required and simplifying the injection device's design. - A further non-limiting embodiment of an injection device according to the present invention is illustrated in
FIGS. 4-19B . - Referring to
FIGS. 4-6 , theinjection device 100 includes ahousing 112, adose selector 116, adose button 130 anddose button spring 131, aunits wheel 118, atens wheel 119, adose indicator spring 117, adrive shaft 140, adrive spring 120, adose limit nut 141, aworm gear 142, aworm gear support 143 and a worm gearrotational lock 144, all located concentrically about a common longitudinal axis L. The axis L extends between afront end 100 a and arear end 100 b of theinjection device 100. - The
injection device 100 has amedicament cartridge 124 supported in acartridge holder 125 at thefront end 100 a of theinjection device 100. Thecartridge 124 is sealed by an axially-moveable cartridge stopper 126 at its rear end. The cartridge and cartridge holder are located concentrically about a second longitudinal axis Lc, such that the cartridge is offset from themain housing 112, with L and Lc offset from one another as shown inFIG. 6 . - The
dose button 130 is biased rearwardly by thedose button spring 131. Thedose selector 116 is provided at therear end 100 b of theinjection device 100 and is arranged to permit the selection of a desired dose of medicament for delivery from themedicament cartridge 124 into an injection site. Thedose selector 116 is axially constrained with respect to thehousing 112 but is rotatable with respect thereto, about axis L. Thedose selector 116 is rotationally coupled to thedrive shaft 140 via pawl features 115, visible inFIG. 7A , which engagesplines 149 on thedrive shaft 140. Thehousing 112 is provided with teeth 113 (visible inFIG. 7B ) on an inside surface thereof for engaging ratchetarms 146 on thedrive shaft 140.Tabs 114 on thedose selector 116 are capable of depressing the drive shaft ratchetarms 146 when required, as shown inFIG. 8B . Thehousing 112 is also provided with ramp features 111 (visible inFIG. 12A ) which facilitate disengagement of theratchet arms 146 from the inside surface of thehousing 112 when required. - A dose indicator is disposed within the
housing 112 and displays reference indicia, such as numbers or symbols, to indicate the level of dose selected by thedose selector 116. Thehousing 112 includes anaperture 112 a through which the dose indicator is visible. The dose indicator comprises the units wheel 118 for displaying units and the tens wheel 119 for displaying tens. The units wheel 118 is selectively engageable with the tens wheel to increment the tens wheel each time the units wheel moves through units 0 to 9. The units wheel 118 is rotationally coupled to thedrive shaft 140. - As with the first embodiment, described with reference to
FIGS. 1-3 , biasing means in the form ofdose indicator spring 117 biases the units wheel 118 and tens wheel 119 axially rearwardly in the housing. - The
housing 112 has features on an inside surface thereof for engaging with the units wheel 118 and the tens wheel 119. - An internal surface of the
housing 112 is provided with atens housing feature 108 selectively engageable with the tens wheel 119 to prevent rotation thereof. The tens housing feature comprises one or more axially forwardly extendingformations 108 which may be equally spaced around the internal circumference of thehousing 112. Theformations 108 engage with corresponding axially rearwardly extendingformations 119 b at the rear of the tens wheel 119. The tenshousing feature formations 108 and the tens wheelformations 119 b may be teeth, notches, castellations or any other shaped formations that, when engaged together, prevent relative rotation between the tens wheel 119 and thehousing 112. - An internal surface of the
housing 112 is provided with aunits housing feature 107 capable of moving the units wheel axially-forward against said biasing means 117. The units housing feature is an axiallyforwardly extending formation 107 having a cam surface which can engage with an axiallyrearwardly extending formation 118 b on the units wheel 118 in order to push the units wheel 118 axially forwards. -
Teeth 118 a on the front end of the units wheel 118 are engageable with correspondingly shapedteeth 119 a at the rear end of the tens wheel 119. On the tens wheel 119, theteeth 119 a (for engaging the units wheel) and the tens wheelformations 119 b (for engaging the housing) may be concentrically arranged around the longitudinal axis of the injection device, with theteeth 119 a radially inward of theformations 119 b. - The
drive spring 120 is a torsion spring which is fixed at one end with respect to thehousing 112 and rotationally coupled at its other end to thedrive shaft 140 via the units wheel 118. - A worm gear arrangement is provided which comprises a
worm gear 142 meshed with atoothed plunger rack 145 located within thehousing 112. During dose delivery, theworm gear 142 drives theplunger rack 145 forward which, in turn, pushes against thecartridge stopper 126 to deliver a dose of medicament. Asplined clutch 150 at the forward end of thedrive shaft 140 enables theworm gear 142 and driveshaft 140 to be splined together during dose delivery but not during dose setting, described in more detail later. InFIG. 6 , the worm gearrotational lock 144 is engaged in the forward end of theworm gear 142, preventing rotation thereof. The worm gearrotational lock 144 is capable of being pushed axially forward by thedrive shaft 140 in order to disengage the lock from theworm gear 142. - The
dose limit nut 141 is keyed to thedrive shaft 140 so that they are rotationally coupled but not axially coupled. Thedose limit nut 141 is engaged with the teeth of theplunger rack 145 and can travel axially forward and backward along theplunger rack 145 as the dose is incremented or decremented respectively. The axial range within which thedose limit nut 141 can travel along theplunger rack 145 is determined by dose limit nut endstop features 141 a, 141 b which can engagefeatures dose limit nut 141.FIG. 5A shows the maximum dose limit nut endstop feature 141 a and the minimum dose limit nut endstop feature 141 b in more detail.Endstops features FIG. 5B ). Thesefeatures dose limit nut 141 cannot travel. During dose delivery, thedose limit nut 141 rotates about axis L with thedrive shaft 140 to which it is keyed, but it does not move axially with respect to theplunger rack 145 with which it is engaged, thus always keeping thedose limit nut 141 within the range defined by the max/min dose endstops 141 a, 141 b. - The operation of the respective features of the
injection device 100 will now be described in more detail below. - With the
injection device 100 in the configuration shown inFIG. 7 , the user grips thedose selector 116 and rotates it clockwise about axis L, with respect to thehousing 112, in order to increment the dose and charge thedrive spring 120. As thedose selector 116 is turned clockwise, the pawl features 115 engaging thesplines 149 on thedrive shaft 140 cause thedrive shaft 140 to also be driven clockwise, as shown inFIG. 7A . - While the dose is being incremented, the
ratchet arms 146 on thedrive shaft 140 engage with theteeth 113 on the inside surface of thehousing 112 to prevent un-winding by thedrive spring 120, as shown inFIG. 7B . - As shown in
FIG. 7C , thedrive shaft 140 is splined to the units wheel 118 which charges or torques up thedrive spring 120. In other words, torque is transferred from thedose selector 116 to thedrive spring 120 directly through the dose indicator, i.e. the units wheel 118. - When it is desired to decrement the selected dose, the
dose selector 116 is turned anti-clockwise. As shown inFIG. 8A , as thedose selector 116 is turned anti-clockwise, there is a small amount of backlash at point A such that thedose selector 116 can rotate slightly with respect to thedrive shaft 140. This small relative movement is sufficient to allow thetabs 114 on thedose selector 116 to depress the drive shaft ratchetarms 146 so that they can click past thehousing teeth 113, allowing the drive spring to unwind slightly before theratchet arms 146 catch again on thenext housing tooth 113. This is represented inFIG. 8B . Each decrement preferably equates to 1 IU (“international unit”) of medicament. - As the
drive shaft 140 is rotated during dose setting, thedose limit nut 141, which is keyed to thedrive shaft 140, is also rotated (FIG. 9A ). Thedose limit nut 141 travels forwards when incrementing the dose and rearwards when decrementing the dose (FIG. 9B ). Thedose limit nut 141 is engaged in the thread of theplunger rack 145. Endstop features 147, 148 are located on theplunger rack 145, past which thedose limit nut 141 cannot travel (FIG. 9C ). These endstop features 147, 148 may be changes in the depth of the thread. As shown inFIG. 9D , when thedose limit nut 141 rotates into a position wherein the dose limit nut endstop feature 141 a engagesfeature 147 on theplunger rack 145, further rotation of thedose limit nut 141 is prevented so that a dose of medicament greater than the desired maximum dose of medicament cannot be set. Limiting the travel of thedose limit nut 141 sets the maximum and minimum doses of medicament that can be set during dose setting, preferably 100 IU and 0 IU respectively. - As shown in
FIG. 10A , in the event the user applies too much force (over torque) to thedose selector 116 in either rotational direction, the dose selector pawl features 115 will flex radially outwardly to allow them to skippast splines 149 on thedrive shaft 140. Preferably the interfacing surface areas of the pawl features 115 and/orsplines 149 act as a cam lever, preferably having a matching angle and/or a defined static and dynamic surface friction at the interface surface. The over-torque for flexing out the dose pawl features 115 to skippast spline 149 is preferably at least 10% higher than the torque required for dialling up (incrementing) or dialling down (decrementing) thedose indicator flexible pawl arm 115 could be lower compared to a second flexible pawl arm. -
FIG. 16 summarises schematically the mechanical motion of thedrive shaft 140,dose limit nut 141,worm gear 142 andplunger rack 145 during dose setting (incrementing the dose). Thedrive shaft 140 rotates clockwise. Thedose limit nut 141 rotates clockwise and advances forwards with respect to theplunger rack 145. - To initiate dose delivery, the user presses the
dose button 130 against the bias of thedose button spring 131 as shown inFIG. 11A . This pushes thedrive shaft 140 axially forwards. Although thedrive shaft 140 is splined to the units wheel 118, it is free to slide axially with respect thereto (FIG. 11B ). - As the
drive shaft 140 advances, at its forward end, thesplined clutch 150 between the drive shaft and theworm gear 142 engages (FIG. 11C ,FIG. 15 —Worm Gear Clutch 150). Preferably the drive element, in particular theworm gear 142 and thedrive shaft 140 engage after 0.5 mm to 1.5 mm advancement of thedose button 130, more preferably after 0.8 mm to 1.2 mm advancement of thedose button 130. Once the clutch 150 has started to engage, theratchet arms 146 on thedrive shaft 140 begin to disengage from the inside surface of thehousing 112 aided by ramp features 111 (FIG. 12A ,FIG. 15 —Hold Ratchet). Preferably the hold ratchet, in particular theratchet arms 146 on thedrive shaft 140 start to disengage from the structured, in particular toothed surface of thehousing 112 after 1.5 mm to 2.5 mm advancement of thedose button 130, more preferably after 1.6 mm to 1.9 mm advancement of thedose button 130. Also, as thedrive shaft 140 moves forward, thesplines 149 coupling thedrive shaft 140 to thedose selector 116 disengage (FIG. 12B ,FIG. 15 —Over torque ratchet). Preferably the over torque ratchet, in particular the drive shaft splines 149 on thedrive shaft 140 start to disengage from thedose selector pawls 115 after 1.5 mm to 3.5 mm of advancement of thedose button 130, more preferably after 2 mm to 3 mm advancement of thedose button 130. The dose indicator and driveshaft 140 are now free to rotate about longitudinal axis L. - The
drive spring 120 drives the units wheel 118 to rotate about longitudinal axis L. The units wheel 118 drives thedrive shaft 140 which drives theworm gear 142. -
FIG. 17 summarises schematically the mechanical motion of thedrive shaft 140,dose limit nut 141,worm gear 142 andplunger rack 145 during dose delivery. Thedrive shaft 140,dose limit nut 141 andworm gear 142 all rotate anti-clockwise. Only theplunger rack 145 advances forwards. During dose delivery, thedose limit nut 141 rotates with thedrive shaft 140 but does not move axially with theplunger rack 145. Thedose limit nut 141 and thedrive worm gear 142 preferably have the same thread pitch. - The
worm gear 142 actuates theplunger rack 145 to move axially forwards causing thecartridge stopper 126 to be driven into the cartridge in order to expel medicament thus delivering the selected dose. - When the
dose button 130 is released, thedose button spring 131 returns thedose button 130 and driveshaft 140 to their original starting positions. This axially rearward movement disengages theworm gear clutch 150 and re-engages the drive shaft ratchetarms 146 with thehousing 112 thereby stopping dose delivery. - During dose delivery, the drive shaft ratchet
arms 146 run (rotationally) on a relativelysmooth track 110 on the inside surface of the housing 112 (FIG. 13A ). Optionally, this track could be modified to includeridges 109 which would provide audible/haptic feedback to the user during dose delivery (FIG. 13B ). Theridges 109 are conveniently placed relatively close to the user's fingers. - When the
medicament cartridge 124 is relatively empty, after several doses have already been delivered therefrom, it is undesirable for the user to be able to select a dose that is larger than the available quantity of medicament remaining. Last dose protection is provided to deal with this situation. Conveniently, the last dose protection is provided by the same feature as the max/min dose limiting i.e. thedose limit nut 141. - As shown in
FIG. 14 , after several doses have been delivered, theplunger rack 145 anddose limit nut 141 have advanced axially forwards such that thedose limit nut 141 is approaching theworm gear 142. When there is less than a predetermined amount (e.g. 100 IU) of medicament available, theworm gear 142 serves as an endstop, stopping thedose limit nut 141 from moving further forwards and before the maximumdose limit feature 147 on theplunger rack 145 is reached (FIG. 14A ). Preferably, it is the dose limit nut endstop feature for maximum dose limiting 141 a which engages theworm gear 142. If the user tries to increment the dose further, torque is transmitted through thedose limit nut 141 into theworm gear 142, the torque being reacted to by the worm gear rotational lock 144 (FIG. 14B ). As such, theworm gear 142 is unable to rotate due to rotational engagement with therotational lock 144. - During dose delivery, when the
drive shaft 140 is moved axially forwards, theworm gear clutch 150 is engaged before the worm gearrotational lock 144 is disengaged (FIG. 14C ). The axially-forward movement of thedrive shaft 140 causes its forward end to push the worm gearrotational lock 144 out of the front of theworm gear 142. With the worm gearrotational lock 144 disengaged, theworm gear 142 is free to rotate, driven by the drive shaft 140 (FIG. 14D ). Once dose delivery is finished, thedrive shaft 140 moves rearwardly. The worm gearrotational lock 144 re-engages, before theworm gear clutch 150 is disengaged (FIG. 14E ). -
FIG. 15 is a diagrammatic summary of the key engagement points of the injection device components, at four stages of dose delivery. - As already described above, during dose selection the user rotates the
dose selector 116 which also drives thedrive shaft 140 around.Ratchet arms 146 interact withteeth 113 in thehousing 112 to prevent unwinding (FIG. 18A ). Thedrive shaft 140 is splined to the units wheel 118 which, as it turns, increments the displayed unit (FIG. 18B ). - The units wheel 118 and tens wheel 119 are biased rearwardly by
dose indicator spring 117. Twice per revolution of the units wheel 118, the units wheel 118 is moved axially forwards by the cam surface of theunits housing feature 107 engaging with theformation 118 b on the units wheel 118. This axially forward movement causes theteeth 118 a of the units wheel 118 to engage with theteeth 119 a of the tens wheel 119 (FIG. 19A ). Continued forward axial movement of the units wheel 118 pushes theformations 119 b of the tens wheel 119 away from thetens housing feature 108, so that the tens wheel 119 is free to rotate with respect to thehousing 112, allowing the tens wheel 119 to be driven around by the units wheel 118 by one increment (FIG. 19B ). - In a preferred embodiment, the selectable and settable dose range is 1 to 100 IU, with a minimum dose setting of 1 IU, wherein per 360 degree rotation of the
dose selector injection device - As with the first embodiment, described with reference to
FIGS. 1-3 , adose limit nut 141 and a plunger element (plunger rack 145) are each threaded so that thedose limit nut 141 is engaged with saidplunger element 145 via said thread, in order to guide relative axial movement between thedose limit nut 141 and theplunger element 145. - The thread is provided with
dose limiting endstops dose limit nut 141 with respect to saidplunger element 145, so as to limit maximum and minimum doses of medicament which can be set by the user. - The
dose limit nut 141 is also engageable with a last dose rotary endstop (worm gear 142) which prevents further rotation of thedose limit nut 141 with respect to thedrive shaft 140 so as to prevent the user setting a dose that is greater than an injectable volume of medicament remaining in said medicament container. - Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.
- Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
- The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.
- 10 injection device
- L longitudinal axis
- 10 a front end of the device
- 10 b rear end of the device
- 12 housing
- 14 needle
- 16 dose selector
- 18 dose indicator
- 20 spring
- 22 drive assembly
- 24 medicament container
- 26 force path
- 40 drive shaft
- 41 dose limit nut
- 42 last dose rotary endstop feature
- 45 plunger element
- 47, 48 dose limit nut endstop features
- 100 injection device
- L longitudinal axis (housing)
- Lc second longitudinal axis (cartridge)
- 100 a front end of the device
- 100 b rear end of the device
- 107 units housing feature
- 108 tens housing feature
- 109 housing ridge features
- 110 housing smooth inside surface track
- 111 housing ramps for drive shaft ratchet arms
- 112 housing
- 112 a aperture in the housing
- 113 housing teeth
- 114 tabs
- 115 dose selector pawl
- 116 dose selector
- 117 dose indicator spring
- 118 units wheel
- 118 a teeth on units wheel (for engaging tens wheel)
- 118 b formation on units wheel (for engaging units housing feature)
- 119 tens wheel
- 119 a teeth on tens wheel (for engaging units wheel)
- 119 b formations on tens wheel (for engaging tens housing feature)
- 120 drive spring
- 124 medicament cartridge
- 125 cartridge holder
- 126 cartridge stopper
- 130 dose button
- 131 dose button spring
- 140 drive shaft
- 141 dose limit nut
- 141 a dose limit nut endstop feature for max dose limiting and last dose limiting
- 141 b dose limit nut endstop feature for min dose limiting
- 142 worm gear
- 143 worm gear support
- 144 worm gear rotational lock
- 145 plunger rack
- 146 drive shaft ratchet arms
- 147 max dose endstop on plunger rack for dose limit nut
- 148 min dose endstop on plunger rack for dose limit nut
- 149 drive shaft splines
- 150 worm gear clutch
- A backlash point for over-torque protection
Claims (19)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1615455.1 | 2016-09-12 | ||
GBGB1615455.1A GB201615455D0 (en) | 2016-09-12 | 2016-09-12 | Last dose protection |
GB1615455 | 2016-09-12 | ||
PCT/EP2017/072723 WO2018046721A1 (en) | 2016-09-12 | 2017-09-11 | Dose limiting mechanism |
Publications (2)
Publication Number | Publication Date |
---|---|
US20190366007A1 true US20190366007A1 (en) | 2019-12-05 |
US11324893B2 US11324893B2 (en) | 2022-05-10 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/332,198 Active 2037-12-17 US11324893B2 (en) | 2016-09-12 | 2017-09-11 | Dose limiting mechanism |
Country Status (4)
Country | Link |
---|---|
US (1) | US11324893B2 (en) |
EP (1) | EP3509676B1 (en) |
GB (1) | GB201615455D0 (en) |
WO (1) | WO2018046721A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
IT202100012020A1 (en) | 2021-05-11 | 2022-11-11 | Stevanato Group Spa | Drug injection device |
IT202100032357A1 (en) | 2021-12-23 | 2023-06-23 | Stevanato Group Spa | Drug injection device |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2021099992A2 (en) * | 2019-11-21 | 2021-05-27 | Ben David Ishai | Liquid delivery device and method |
Family Cites Families (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2531879B1 (en) * | 1982-08-17 | 1985-09-13 | Anbar Gassan | FLUID PRODUCT DISPENSER |
TW453884B (en) | 1999-09-16 | 2001-09-11 | Novo Nordisk As | Dose setting limiter |
DE10046279A1 (en) * | 2000-09-19 | 2002-04-04 | Disetronic Licensing Ag | Device for the dosed administration of an injectable product |
DE102004063644A1 (en) | 2004-12-31 | 2006-07-20 | Tecpharma Licensing Ag | Device for the dosed administration of a fluid product with torsion spring drive |
US20090054851A1 (en) | 2005-02-17 | 2009-02-26 | Novo Nordisk A/S | dose setting element for an injection device and having a dose setting limiting mechanism |
EP1909870B2 (en) | 2005-07-27 | 2016-01-20 | Novo Nordisk A/S | Dose mechanism for an injection device for limiting a dose setting corresponding to the amount of medicament left |
WO2008101829A1 (en) * | 2007-02-20 | 2008-08-28 | Novo Nordisk A/S | An injection device comprising a worm gear connection |
EP2482901B1 (en) * | 2009-09-30 | 2019-10-23 | Sanofi-Aventis Deutschland GmbH | Injection device |
DK3733231T3 (en) | 2009-12-01 | 2022-03-07 | Becton Dickinson Co | Injection pen with automatic retraction (dial back) and control of the last dose |
EP2838586B1 (en) * | 2012-04-20 | 2016-02-17 | Novo Nordisk A/S | Medical injection device comprising a secondary safety limiter |
WO2013178372A1 (en) | 2012-05-31 | 2013-12-05 | Novo Nordisk A/S | Dial-down mechanism for wind-up pen |
DK2983741T3 (en) | 2013-04-10 | 2020-08-24 | Sanofi Sa | PENTYPLE MEDICINE INJECTION DEVICE AND DOSAGE ADJUSTMENT MECHANISM |
DK2983752T3 (en) * | 2013-04-10 | 2019-08-12 | Sanofi Sa | INJECTION DEVICE |
EP3021911B1 (en) | 2013-07-17 | 2021-07-14 | Sanofi | Drug delivery device |
CN105377335B (en) * | 2013-07-17 | 2020-08-04 | 赛诺菲 | Drug delivery device |
TR201900772T4 (en) * | 2013-09-10 | 2019-02-21 | Sanofi Sa | The drive mechanism of the drug delivery device. |
JP2017516540A (en) | 2014-05-26 | 2017-06-22 | サノフイ | Display device for injection device |
TW201603847A (en) | 2014-07-01 | 2016-02-01 | 賽諾菲公司 | Injection device and assembly method |
JP6632616B2 (en) | 2014-10-09 | 2020-01-22 | サノフイSanofi | Drive mechanism for injection device |
-
2016
- 2016-09-12 GB GBGB1615455.1A patent/GB201615455D0/en not_active Ceased
-
2017
- 2017-09-11 EP EP17767794.5A patent/EP3509676B1/en active Active
- 2017-09-11 US US16/332,198 patent/US11324893B2/en active Active
- 2017-09-11 WO PCT/EP2017/072723 patent/WO2018046721A1/en active Application Filing
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
IT202100012020A1 (en) | 2021-05-11 | 2022-11-11 | Stevanato Group Spa | Drug injection device |
EP4088764A1 (en) | 2021-05-11 | 2022-11-16 | Stevanato Group S.P.A. | Drug injection device |
US20220362477A1 (en) * | 2021-05-11 | 2022-11-17 | Stevanato Group S.P.A. | Drug injection device |
US11696987B2 (en) * | 2021-05-11 | 2023-07-11 | Stevanato Group S.P.A. | Drug injection device |
IT202100032357A1 (en) | 2021-12-23 | 2023-06-23 | Stevanato Group Spa | Drug injection device |
EP4201443A1 (en) | 2021-12-23 | 2023-06-28 | Stevanato Group S.P.A. | Drug injection device |
US11918790B2 (en) | 2021-12-23 | 2024-03-05 | Stevanato Group S.P.A. | Drug injection device |
Also Published As
Publication number | Publication date |
---|---|
WO2018046721A1 (en) | 2018-03-15 |
GB201615455D0 (en) | 2016-10-26 |
US11324893B2 (en) | 2022-05-10 |
EP3509676B1 (en) | 2023-11-08 |
EP3509676A1 (en) | 2019-07-17 |
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